System and method for determining input object information from proximity and force measurements

• US 9,690,438 B2
• Filed: 05/06/2016
• Issued: 06/27/2017
• Est. Priority Date: 06/30/2014
• Status: Active Grant

• Current Assignee: Synaptics Incorporated
• Original Assignee: Synaptics Incorporated
• Inventors: Worfolk, Patrick, Mahalingam, Vijay Venkatesh
• Primary Examiner(s): OLSON, JASON C
• Application Number:
  US15/149,080
• Publication Number:
  US 20160253007A1
• Time in Patent Office: 417 Days
• Field of Search: 345174
• CPC Class Codes: G06F 2203/04101 2.5D-digitiser, i.e. digitiser detecting the X/Y position of the input means, finger or stylus, also when it does not touch, but is proximate to the digitiser's interaction surface and also measures the distance of the input means within a short range in the Z direction, possibly with a separate measurement setup
• CPC Class Codes: G06F 2203/04104 Multi-touch detection in digitiser, i.e. details about the simultaneous detection of a plurality of touching locations, e.g. multiple fingers or pen and finger
• CPC Class Codes: G06F 2203/04105 Pressure sensors for measuring the pressure or force exerted on the touch surface without providing the touch position
• CPC Class Codes: G06F 2203/04106 Multi-sensing digitiser, i.e. digitiser using at least two different sensing technologies simultaneously or alternatively, e.g. for detecting pen and finger, for saving power or for improving position detection
• CPC Class Codes: G06F 3/03545 Pens or stylus
• CPC Class Codes: G06F 3/0416 Control or interface arrangements specially adapted for digitisers
• CPC Class Codes: G06F 3/04186 Touch location disambiguation
• CPC Class Codes: G06F 3/0445 using two or more layers of sensing electrodes, e.g. using two layers of electrodes separated by a dielectric layer
• CPC Class Codes: G06F 3/0446 using a grid-like structure of electrodes in at least two directions, e.g. using row and column electrodes
• CPC Class Codes: G06F 3/0447 Position sensing using the local deformation of sensor cells

Abstract

A processing system for an input device having a sensing region overlapping an input surface and an array of sensor electrodes configured to form a plurality of proximity pixels and a plurality of force pixels. The processing system is configured to: determine a proximity image indicative of positional information for input objects; determine a force image indicative of local deflection of the input surface in response to force applied by the input objects; determine a respective group of proximity pixels from the proximity image corresponding to each input object; determine a respective group of force pixels from the force image corresponding to each determined group of proximity pixels; determine the position of each input object based on the determined groups of proximity pixels; and determine the force associated with each input object based on the determined groups of force pixels.

Claims

1. A processing system for use with an input device having an array of sensor electrodes, the processing system configured to be communicatively coupled to the array of sensor electrodes and configured to:

operate at least a subset of the array of sensor electrodes to determine a proximity image for input objects in a sensing region of the input device;

operate at least a subset of the array of sensor electrodes to determine a force image indicative of local deflection of an input surface of the input device;

determine a first group of proximity pixels from the proximity image corresponding to a first input object in the sensing region to obtain a determined group of proximity pixels;

determine a first group of force pixels from the force image corresponding to the determined first group of proximity pixels to obtain a determined group of force pixels;

determine the force for the first input object based on the determined group of force pixels; and

perform a user interface action based on the force determined for the first input object.

2. The processing system of claim 1, wherein the proximity image is determined from a change in a plurality of variable capacitances formed by the subset of the array of sensor electrodes, wherein each variable capacitance comprises a proximity pixel.

3. The processing system of claim 1, wherein the force image is determined from a change in a plurality of variable capacitances formed by the subset of the array of sensor electrodes, wherein each variable capacitance comprises a force pixel.

4. The processing system of claim 1, further configured to:

determine the position of the first input object based on the determined group of proximity pixels.

5. The processing system of claim 1, wherein the determined first group of force pixels is based on a planar alignment of the proximity pixels relative to the force pixels for the first input object.

6. The processing system of claim 1, wherein the determined first group of force pixels are based on a mapping of one of the determined group of proximity pixels to a corresponding group of force pixels for the first input object, wherein the proximity-to-force pixel mapping comprises one of:

i) a one-to-one;

ii) greater than one-to-one; and

iii) less than one-to-one.

7. The processing system of claim 1, wherein the array of proximity pixels and the array of force pixels formed by the array of sensor electrode share a common array of two-dimensional coordinate locations.

8. The processing system of claim 7, wherein determining the first group of force pixels comprises seeding the first group of force pixels with the coordinate locations of the proximity pixels in the determined group of proximity pixels to obtain a plurality of seeded force pixels.

9. The processing system of claim 1, wherein determining the first group of force pixels from the force image corresponding to the determined group of proximity pixels comprises:

for each force pixel in the force image above a threshold value, assigning that force pixel to the determined group of proximity pixels.

10. The processing system of claim 8, wherein determining the first group of force pixels further comprises removing seeded force pixels, in the plurality of seeded force pixels, having a value less than a threshold value.

11. The processing system of claim 1, wherein the determined force for the first input object is based on a force value associated with each force pixel of the determined group of force pixels.

12. The processing system of claim 11, further configured to determine pressure applied to the input surface by the first input object based on a contact area of the first input object and the determined force for the first input object.

13. The processing system of claim 9, wherein assigning each force pixel in the force image comprises using an image segmentation algorithm which evaluates the force image based on the determined group of proximity pixels for the first input object.

14. The processing system of claim 1, further configured to:

determine a second group of force pixels from the force image having no corresponding determined group of proximity pixels; and

determine a position of a non-conductive input object contacting the input surface based on the determined second group of force pixels and the absence of the corresponding group of proximity pixels.

15. The processing system of claim 1, wherein performing the user interface action comprises updating a display of the input device.

16. The processing system of claim 1, wherein operating at least the subset of the array of sensor electrodes to determine a proximity image and a force image comprises:

transmitting a sensing signal onto a first electrode of the plurality of sensor electrodes;

receiving a first resulting signal from a second electrode of the plurality of sensor electrodes; and

receiving a second resulting signal from a third electrode of the plurality of sensor electrodes;

determining the change in the variable capacitance associated with at least one proximity pixel based on the first resulting signal; and

determine the change in the variable capacitance associated with at least one force pixel based on the second resulting signal.

17. The processing system of claim 16, wherein the change in the variable capacitance associated with at least one proximity pixel occurs in response to the presence of input objects in the sensing region and the change in the variable capacitance associated with at least one force pixel occurs in response to the local deflection of the input surface.

18. An electronic system having an input device, the input device comprising:

a sensing region overlapping an input surface;

a plurality of sensor electrodes configured to form a plurality of proximity pixels and a plurality of force pixels; and

a processing system configured to be communicatively coupled to the plurality of sensor electrodes and configured to;

determine a proximity image and a force image indicative of at least one input object in the sensing region;

determine a first group of proximity pixels from the proximity image corresponding to a first input object of the at least one input object to obtain a determined first group of proximity pixels; and

determine a first group of force pixels, corresponding to the first input object to obtain a determined first group of force pixels.

19. The electronic system of claim 18, wherein the processing system is configured to determine the first group of three pixels by:

seeding a first preliminary group of force pixels with information from the determined group of proximity pixels; and

augmenting the first preliminary group of force pixels with at least one force pixel from the force image which are above a threshold and adjacent to the seeded first preliminary group of force pixels.

20. The electronic system of claim 18, wherein the processing system is further configured to:

determine a second group of proximity pixels from the proximity image corresponding to a second input object to obtain a determined second group of proximity pixels;

determine a second group of force pixels, corresponding to the second input object, by;

seeding a second preliminary group of force pixels with information from the determined group of proximity pixels; and

augmenting the second preliminary group of force pixels with force pixels from the force image which are above a threshold and adjacent to the seeded second preliminary group of force pixels.

21. The electronic system of claim 18, wherein the processing system is further configured to:

control a user interface action based on the determined position and the determined force of the first input object by updating a display of the electronic system.

22. The input device of claim 21, wherein the input surface overlaps the display.